Evaluation of absorbance for crude and purified natural dyes using Senna singueana, Bougainvillea glabra bracts, and Ximenia caffra on DSSC performance parameters

ABSTRACT

Natural dyes extracted from Senna singueana flowers and leaves, Ximenia caffra fruits and Bougainvillea glabra bracts were used as sensitizers to fabricate dye sensitized solar cells (DSSCs). The UV-Vis characterization of these species’ crude and purified natural dyes showed that Senna singueana leaves have broad broadband absorption, followed by Bougainvillea glabra bracts. The absorption intensity of Senna singueana leave and Bougainvillea glabra bract for crude and purified dyes was comparable, indicating their potential in DSSCs performance. The photoelectrochemical performance of the selected dyes used as a sensitizer in DSSCs indicated that Senna singueana leaves attained the highest open-circuit voltage (V_oc) and short circuit current density (J_sc) of 471 mV and 4.32 mA/cm² for crude dye, and 355 mV and 4.87 mA/cm² for purified dye. In contrast, Bougainvillea glabra bract had 380 mV and 3.34 mA/cm² for crude dye and 75 mV and 1.95 mA/cm² for purified dye. The photo-to-electric conversion efficiency of the DSSCs based on Senna singueana leaves as sensitizers were 0.68% (crude) and 0.51% (purified) and that of Bougainvillea glabra bract were 0.45% (crude) and 0.04% (purified). To our best knowledge, this is the first time to report the highest efficiency for Senna singueana leave in DSSC. Various organic solvents were used for purification; however, the photoelectrochemical performance of those extracts demonstrated that crude dyes are more effective than purified dyes as sensitizers in DSSCs application.

KEYWORDS:

• Dye sensitized solar cell
• natural dye
• sensitizers
• absorbance
• photoelectrochemical

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No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Adam Sakalani

Adam Sakalani is a Physics and Mathematics teacher at Tinde Girls' High School, Shinyanga, Tanzania since 2012. He obtained his Master of Science in Physics in 2020 from the University of Dodoma, Dodoma, Tanzania. He did his first degree in Science (Mathematics and Physics) with Education in 2011 from St. John's University of Tanzania, Dodoma, Tanzania. His research interests is on Renewable Energy, particularly Dye Sensitized Solar Cells.

Stanley Mwanga

Stanley Ferdinand Mwanga is a lecturer in the Department of Physics at the University of Dodoma where he has been a faculty member since 2010. He studied PhD in Material Science and Engineering (Energy Materials), 2016 from Nelson Mandela African Institution of Science and Technology, MSc Physics (2012) and BSc with Education (2006) at Unversity of Dar Es Salaam, Tanzania. He has also a Diploma in Education majoring Physics and Mathematics (1999), at Monduli Teachers’ college - Arusha, Tanzania. His research interest is in Dye Sensitized Solar Cells and Perovsikte Solar Cells both Experimental and theoretical. He has collaborated actively with researchers in several disciplines of material science particularly in glasses.

Laxmikanth Cherupally

Dr. Cherupally Laxmikanth was awarded the doctoral degree in Physics from Osmania University, India in the year 2005. Dr Cherupally has more than 20 years of work experience both in teaching and research. Dr Cherupally worked in various universities across India, Eritrea, and Ethiopia. Currently Dr Cherupally has been working at the Department of Physics, the University of Dodoma, Tanzania. To his credit, Dr Cherupally has got more than 40 research articles published in very reputed peer reviewed journals in the fields of glass science and renewable energy. In addition, Dr Cherupally has a quite good number of conference proceeding articles, book chapters, and text books.

Anjaiah Juluru

Dr. J. Anjaiah is received M. Sc. (Physics) degree with distinction in 1998 and awarded Ph. D. in 2005 from Osmania University, India. He is worked as lecturer at Department of Physics, The University of Dodoma, Tanzania, East Africa. Now, he is working as a Professor in Geethanjali College of Engineering & Technology, Keesara, TS, India. His areas of specialization are Glass Science and Solid State Spectroscopy. He published 25 research articles, two book chapters and a book.